1. Field of the Invention
The present invention relates to a probe for checking linear dimensions, like dimensions of mechanical pieces, with support means, an arm movable with respect to the support means and carrying at an end feeler means adapted for touching a piece to be checked, the movable arm defining a longitudinal geometrical axis, connection means for connecting the arm to the support means for allowing the displacement of the feeler means with respect to the support means along two opposite directions, and detection means associated with the arm and the connection means.
2. Description of the Prior Art
As already known, at present there is a developing trend to equip the turning machines and the machining centers with heads or probes for checking linear dimensions of pieces machined, or to be machined, and of the tools.
These heads usually include an arm carrying a feeler element adapted to contact the piece or the tool, a support, devices for connecting the arm to the support-that allow the feeler to displace along one or more axes-and detection means.
The detection means can include position transducers for providing measurement signals (usually of a comparative type), or electrical contacts that open as a consequence of the mechanical contact occuring between the feeler and the surface of the piece (or tool); in the second case, the opening of the electrical contacts provides a logic signal that controls the reading of the measurement signals provided by transducers associated with the slide(s) of the machine tool on which there are installed the head and/or the piece, and/or the tool.
It is obvious that the essential requirements of heads specifically made for similar applications are sturdiness, reproducibility i.e. repeatability of the measurements and small layout dimensions.
In the known heads or probes, among these contrasting requirements there is obtained a not fully satisfying compromise. More specifically, most of the known heads have a moderately acccurate repeatability, due to the fact that the devices coupling the movable arm to the support are based upon systems that involve frictions and clearances.